In active-type distance measuring devices commonly found in recent compact cameras, a light beam is projected from a projector onto a subject to be photographed, and light reflected from the subject is detected by a light receiving sensor. The light receiving sensor has a plurality of slender light receiving elements disposed side by side in the direction of a base line. The distance to the subject is obtained, based on the position of the light receiving element on which reflected light falls, the light receiving element being identified electrically.